Webster and Bense both strongly considered taking on Nelson in 2006, but both would have had a hard time beating Harris.

Now, Nelson is chasing a third term, seeking to remain the last Democratic statewide officeholder in Florida.

Republicans have a deeper bench of capable candidates than Democrats do. But the best the GOP can come up with against Nelson this time is Connie Mack IV, son of the former senator and a member of Congress since 2004 whose past as a one time consultant for Hooters is not very, well, senatorial.

But Mack's huge lead in the polls in a weak Republican primary field led former U.S. Sen. George LeMieux to quit the race last week. That leaves little-known rivals, including retired U.S. Army Col. Mike McCalister and former U.S. Rep. Dave Weldon, standing between Mack and a November matchup with Nelson.

Nelson is not invincible. Far from it. All summer and fall, TV viewers will see ads featuring endless freeze frames of a smiling Nelson alongside President Barack Obama.

He'll be pilloried as a liberal. But Nelson has raised nearly $12 million, has deep family roots in the Panhandle, and has won statewide office four times.

He runs scared, even when he's ahead, and a Quinnipiac survey last week showed Mack four points behind him.

Mack decided not to debate his GOP rivals in the primary, which may prove to be a strategic mistake, because the practice would have been good for him. Mack won't be able to duck a TV debate in the fall against Nelson, an experienced debater.